Whenever a vacancy occurs in the office of mayor in the City of Prichard in Mobile County, Alabama, with six months or more remaining in the vacating mayor’s term, the president of the city council shall immediately instruct the city clerk to provide for holding a special election to fill such vacancy with such election to be held no later than 60 days after such office has become vacant. Such election shall be held in the manner prescribed by law and the person elected to the office of mayor in such special election shall serve for the remainder of the unexpired term. In the event such vacancy occurs during the last six months of a mayor's term, the president of the city council shall succeed to the office of mayor for the remainder of the unexpired term.