disagreement as to what staff is necessary for this purpose the question shall be decided by the President in his discretion.
140. Function of Election Commission.- The Election Commission shall be charged with the duty of—
(a) preparing electoral rolls for elections to the National Assembly and the Provincial Assemblies, and revising such rolls annually; and
(b) Organizing and conducting elections to the National Assembly and the Provincial Assemblies.
141. Time of election and by-election.- Whenever the National Assembly or a Provincial Assembly is dissolved, a general election for the reconstitution of the Assembly shall be held not later than six months from the date of dissolution; and whenever a casual vacancy occurs in any such Assembly, a by-election to fill the vacancy shall be held not later than three months from the date of the occurrence of the vacancy:
Provided that the Chief Election Commissioner may, if in his opinion climatic conditions so require, hold a by-election at any time after three months, but not later than six months, from the date of the occurrence of the vacancy.
142. Delimitation Commission (1) The President may from time to time constitute a Delimitation Commission consisting of a Chairman who is, or has been a Judge of a High Court, and two other members who shall not be members of the National Assembly or of a Provincial Assembly.
(2) The Chairman and other members of the Delimitation Commission shall be appointed by the President for such period as the President may fix, shall hold office during the pleasure of the President, and shall be entitled to such remuneration and privileges as may be determined by the President.
(3) In the exercise of his functions under the two preceding clauses the President shall act in his discretion.
(4) The Delimitation Commission shall have power to delimit territorial constituencies for election to the National Assembly and Provincial Assemblies and shall publish lists of such constituencies by public notification.
(5) The validity of anything done by or under the authority of the Delimitation Commission shall not be called in question in any court.
143. Qualifications of electors.- (1) A person shall be entitled to be an elector in a constituency if-
(a) he is a citizen of Pakistan;
(b) he is not less than twenty-one years of age on the first day of January in the year in which the preparation or revision of the electoral roll commences;
(c) he is not declared by a competent court to be unsound mind;
