If a vacancy occurs in the office of Mayor, the Vice-Mayor shall become Mayor for the duration of the unexpired term. If a vacancy occurs in the office of Vice-Mayor, the City Council, by an affirmative vote of at least four (4) members, shall select another Vice-Mayor from among its members for the duration of the unexpired term. If a vacancy occurs in the office of Councilman, the City Council shall select, by an affirmative vote of at least four (4) members, an eligible person to fill the vacancy at the next regular meeting of the City Council following the creation of the vacancy or as soon thereafter as is practical.