(a) There shall be established three council districts to be designated respectively as district post 1, district post 2, and district post 3, and in such Class 6 cities, there shall be established four council districts with eight district posts to be designated district 1 post 1, district 1 post 2, district 2 post 1, district 2 post 2, district 3 post 1, district 3 post 2, district 4 post 1, and district 4 post 2. Such districts shall have, as nearly as is reasonable, the same population. The designation and boundaries of the initial council districts shall be specifically described and set forth. In all cities to which this section applies, except the above-described Class 6 cities, the two at-large posts on the council shall be designated as mayor and councilman-at-large; and in such Class 6 cities the one at-large post on the council shall be designated as mayor.
(b) This section shall not apply to a Class 6 municipality with a nine-member council authorized pursuant to Section 11-43A-8 or a Class 7 municipality with a five-member council elected at-large authorized pursuant to Section 11-43A-3.3.