Ordinances and resolutions adopted by Council shall be subject to referendum to the extent and in the manner now or hereafter provided by the Constitution or the laws of the State of Ohio, except that such ordinances and resolutions subjected to referendum shall be submitted to the electors for approval or rejection at the next succeeding general election or primary election occurring subsequent to ninety days after the certifying of such referendum petition to the Board of Elections or a special election to be held on a date fixed by the Council by an affirmative vote of at least four members thereof and certified by the Clerk of Council to the Board of Elections, and except that referendum petitions shall be filed with the Clerk of Council.