The Mayor and each Councilman who held office on the effective date of this Charter shall be the Mayor and Councilmen of the City under this Charter and shall perform their duties under and otherwise be subject to its provisions. Each such officer shall hold and continue in the office held by him, until he or his successor is re-elected or elected or appointed in the case of a vacancy, under the provisions of this Charter. At the City election held in April, 1957, a Municipal Judge shall be elected for a six year term under the provisions of this Charter. The Municipal Judge who held office on the effective date of this Charter shall continue in office and his term shall terminate on the 1st day of January, 1958, at which time the office shall be filled by the person elected to that office at the April, 1957, regular City election. The terms of office specified in this section are for the purpose of bringing the transition from the schedule of terms of office in the former Charter of the City and those provided in this Charter.