(a) Whenever a vacancy occurs in the office of council member in a city of the first class having a population of less than twenty thousand (20,000) according to the most recent federal decennial census, at the first regular meeting after the occurrence of the vacancy, the vacancy shall be filled under § 14-42-103.
(b) When a vacancy occurs in any position of council member in a city having a population of twenty thousand (20,000) or more according to the most recent federal decennial census, the vacancy shall be filled under § 14-42-103.