Such supernumerary tax collector, tax assessor, license commissioner, or other elected official charged with the assessment and/or collection of any ad valorem taxes in the various counties of the State of Alabama shall take the oath of office prescribed for tax collectors, tax assessors, license commissioners, or other elected officials charged with the assessment and/or collection of any ad valorem taxes in this state; and, if a vacancy shall occur in the office in the county in which the supernumerary tax collector, tax assessor, license commissioner, or other elected official charged with the assessment and/or collection of any ad valorem taxes holds his commission, he shall immediately assume and exercise all of the duties, power, and authority of such official in said county until a successor is appointed by the Governor of the State of Alabama.