At the first state general election, one senator shall be chosen for a two-year term from each of the following senate districts, described in section 2 of article XIV: A, B, D, E, G, I, J, L, N, and O. At the same election, one senator shall be chosen for a four-year term from each of the following senate districts described in section 2 of article XIV: A, C, E, F, H, J, K, M, N, and P.