<s>[INST]What are the changes brought about by the Constitution (First Amendment) Act, 1951, s. 13 in terms of office tenure for the person who was Auditor-General immediately before the commencement of this Constitution?. [/INST]The changes brought about by the Constitution (First Amendment) Act, 1951, s. 13 in terms of office tenure for the person who was Auditor-General immediately before the commencement of this Constitution are not explicitly mentioned in the provided context. However, it can be understood that the person will continue to hold office until the expiration of his term of office as determined under the provisions which were applicable to him immediately before such commencement.</s> 