Section 139 in Indian Evidence Act 1872
Title: Cross examination of person called to produce a document
A person summoned to produce a document does not become a witness by the mere fact that he produces it and cannot be cross-examined unless and until he is called as a witness.
Title: Witnesses to character
Witnesses to character may be cross-examined and re-examined
Title: Leading questions
Any question suggesting the answer which the person putting it wishes or expects to receive is called a leading question
Title: When they must not be asked
Leading questions must not, if objected to by the adverse party be asked in an examination-in-chief, or in a re-examination, except with the permission of the Court.
The Court shall permit leading questions as to matters which are introductory or undisputed, or which have, in its opinion, been already sufficiently proved.
Title: When they may be asked
Leading questions may be asked in cross-examination