With respect to municipal elections, each candidate shall announce that he is to become a candidate for either mayor or for councilman of District 1, 2, 3, 4, 5, 6 or 7. A candidate may not run for both mayor and councilman in the same election. A candidate for mayor shall have resided in the municipality for a period of at least ninety days immediately preceding the date of regular election, and, if elected, shall continue to reside therein so long as he remains mayor. A candidate for councilman shall have resided within the district from which he seeks election for a period of at least ninety days immediately preceding the date of the regular election, and, if elected, shall continue to reside therein so long as he remains a councilman. Each voter in the election may cast one vote for a candidate for mayor and one vote for a candidate for councilman from the district in which the voter resides. Any candidate receiving a majority of the total votes cast for mayor or a majority of the total votes cast for councilman from any particular district shall be elected. In the event that no candidate receives a majority, then there shall be a runoff election for any such office to be held in a manner prescribed by the applicable general municipal election laws. The mayor and councilmen elected shall hold office for terms of four years each and shall serve until their respective successors have been elected and qualified. The mayor and councilmen may succeed themselves in office.