Section 15. Term of 5Mayor and 5 * * * .

15. 1[ (1) Except as otherwise provided in this Act, (a) the term of office of a 2[Mayor] shall be co-terminus with the term of the Corporation ; ] (b) 3[ * * * * ] (2) The term of office of a 2[Mayor] or an 4[ * * * ] elected to fill a casual vacancy shall be the remainder of the term of office of his predecessor. (3) A 2[Mayor] or an 4[ * * * ] shall, unless he resigns or ceases to be qualified or becomes disqualified, continue in office until his successor assumes office as 2[Mayor] or 4[ * * * ] as the case may be. 15-A. 5[ * * * * * ]