In the principal Act, in section 13, for the words beginning with "by election of a suitable person" and ending with the words "if the vacancy had not occurred", the words and figures "by election or nomination, as the case may be, of a suitable person in accordance with the provisions of section 11 and any person so elected or nominated to fill a vacancy shall hold office only so long as the member in whose place he is elected or nominated would have held office, if the vacancy had not occurred" shall be substituted.