There is hereby formed, pursuant to article 10, section 9C of the constitution of the state of Oklahoma, an emergency medical service district (i.e., an ambulance service district) which is hereinafter referred to as "district"; subject, however, to approval of the registered voters of the city at a special election hereby called, at which all registered voters residing in the city shall be entitled to vote as to whether or not such district shall be formed, and at which election the registered voters at the same time and in the same question will vote on whether to authorize a tax levy not to exceed zero mills. (1991 Code § 11-26)