If an initiative or a referendum petition is found to be legal and to have sufficient signatures, the City Clerk, with such assistance from the City Attorney as the City Clerk deems necessary, shall prepare the ballot title and propositions for the ordinance. The City Clerk shall place the question on the ballot for the next regular or special City election held not less than two (2) months after final determination of the legality and sufficiency of the petition. The Council by resolution or ordinance may call, or authorize the Mayor by proclamation to call, a special election for the purpose. If, in the case of an initiative petition, the Council, at least one month before the election, enacts an ordinance substantially the same as the one in the petition, the petition shall be void.