If an election is to be held not more than ninety (90) days nor less than thirty (30) days after the publication of such notice by the clerk, such proposed ordinance shall be submitted to a vote of the electors at such election. If no election is to be held within the time aforesaid, the election officers shall provide for submitting the proposed ordinance to the electors at a special election to be held no later than sixty (60) days nor earlier than thirty (30) days after the publication of such notice, if the petition for such ordinance and the petition for such election so demand, and if the signers of the two petitions amount in the aggregate to at least twenty-five percent (25%) of the registered voters in the municipality at the last regular municipal election. At least ten (10) days before any such election the clerk of the city commission shall cause such proposed ordinance to be published.