law: 15. Filling of a casual vacancy.
  (1) When the seat of a member becomes vacant by his removal, resignation, death or otherwise, a new member shall be nominated or elected, as the case may be, in his place and such member shall hold office so long as the member whose place he fills would have been entitled to hold office if such vacancy had not occurred.
  (2) Any casual vacancy under sub-section (1) shall be filled up by the same category to which the former member belonged.