When a person receives an Aliya to the Torah, the reader should show him the place where the Aliya will begin. He then kisses that spot in the Torah and recites the Beracha. It occasionally happens that the reader makes a mistake and shows the wrong place to the one receiving the Aliya. This is especially prone to happen when the Aliya begins with a common verse – such as "Va’yedaber Hashem El Moshe Lemor" – and the reader can thus easily become confused. The Shulhan Aruch (140:3) cites two views as to whether the one who receives the Aliya must repeat the Beracha if he had recited the Beracha after looking at the wrong place. The first opinion – which the Shulhan Aruch cites with the words "Yesh Omrim" ("There are those who say") – maintains that the one receiving the Aliya does not have to repeat the Beracha in this case. The reason for this ruling is that the Beracha does not relate to any particular spot in the Torah, but rather to the Torah generally. The second opinion, however, which is also introduced with the term "Yesh Omrim," maintains that the person must, in fact, repeat the Beracha.
There is a general rule that when the Shulhan Aruch cites two views in this format – "Yesh Omim… Ve’yesh Omrim" – he sides with the second view. Accordingly, his position is that the one receiving the Aliya must repeat the Beracha if he had recited it after looking at the wrong place. Interestingly, the Taz (Rav David Ha’levi Segal, 1586-1667), cited by the Mishna Berura, writes that this ruling applies only if the person receiving the Aliya looked at text on a different page in the Torah scroll. According to the Taz, if the one receiving the Aliya looked at the wrong place but it was on the right page, then all agree that the Beracha is not repeated. Others maintain that as long as the place the person looked at was within that day’s Torah reading, even if it was not where his Aliya was beginning, he does not have to repeat the Beracha.
The Kaf Ha’haim (Rav Yaakob Haim Sofer, Baghdad-Israel, 1867-1939), however, writes that this discussion is of no practical relevance, because of the famous rule of "Safek Berachot Le’hakel" – we do not recite a Beracha when there is some uncertainty as to whether it is required. Even when the Shulhan Aruch requires reciting a Beracha, the Beracha should not be recited if other authorities disagree and maintain that it is not required. Hence, in this case, since some authorities maintain that the Beracha should not be repeated, the person receiving the Aliya does not repeat the Beracha if he had recited it over the wrong place. This is especially so in light of the position of the Rambam (Rav Moshe Maimonides, Spain-Egypt, 1135-1204) that one can recite a Beracha when reading from an invalid Sefer Torah. Clearly, in his view, the Beracha relates to the reading in general, and not to any particular spot in the Torah scroll, and thus it would not have to be repeated if one recited it after being shown the wrong place. This is the conclusion of Hacham David Yosef, in his Halacha Berura.
All the people standing at the Teba during the Torah reading – the reader, the Somech, and the one receiving the Aliya – must stand. This Halacha is established by the Talmud Yerushalmi, which explains that standing is required either out of respect for the Sefer Torah, or out of respect for the congregation.
It is forbidden to lean on the Teba when the Torah is being read, unless one is elderly or otherwise frail, in which case he may lean on the Teba for support. Even in such a case, however, it is forbidden to lean all of one’s weight on the Teba such that he would fall if the Teba would be removed from underneath him. He may lean for extra support, but may not lean all his weight on the Teba. Furthermore, if the Torah sits on a cloth on the Teba, it would be forbidden to lean on the cloth, and the person would have to lift the cloth and lean directly on the surface of the Teba. If one leaned on the Teba while reading the Torah, the reading does not have to be repeated. Nevertheless, if this occurred on Shabbat, when extra Aliyot may be added, it is preferable to add an extra Aliya.
The Shulhan Aruch writes that the one receiving the Aliya must read the text along with the reader. This is mentioned also by the Zohar, which writes that the one receiving the Aliya should read in a low voice, which is inaudible even to himself, the way one recites the Amida. The Shulhan Aruch goes so far as to say that if the one receiving the Aliya does not read the text along with the reader, his Beracha might constitute a Beracha Le’batala (Beracha recited in vain). We do not apply the famous rule of "Shome’a Ke’oneh" – that listening to a recitation is equivalent to personally reciting the text – because the reader does not actually bear an obligation to read. The obligation of Torah reading is borne by the congregation as a whole, and not by the reader personally. The mechanism of "Shome’a Ke’oneh" can be used only when one who bears the obligation recites the required recitation and the others fulfill their obligation by listening. It cannot be used in this case, when the reader does not bear a personal obligation.
Therefore, according to the Shulhan Aruch, somebody who cannot read along the reader, either because of a visual impairment or because he is ignorant, may not be given an Aliya to the Torah. Other Halachic authorities (including the Aruch Ha’shulhan) disagree, and maintain that we may rely on the concept of "Shome’a Ke’oneh" even for the Torah reading. However, in light of the Shulhan Aruch’s ruling, the question arises as to why many congregations call for Aliyot even those who are clearly incapable of reading along with the Hazan, and just stand there silently. This topic requires further analysis, but clearly, one who receives an Aliya and is capable of reading along with the reader must do so. As mentioned, this should be done in a very low voice, as the Zohar requires, and so as not to confuse the reader.
Summary: When one receives an Aliya, he should be first shown the place where the Aliya will be starting, and only then recite the Beracha. If he is shown the wrong place and then recites the Beracha, he does not have to repeat the Beracha. One may not lean on the Teba during the reading, unless he is ill or frail, in which case he may lean slightly, without resting all his weight on the Teba. During the reading, the one who receives the Aliya must quietly read the text along with the reader.