Complex sentence: After his election as Mayor, he served the city until 1990, when Filiberto ran instead in the 1990 Republican Primary for the 2nd Congressional District seat in Florida, then held by Bill Nelson, who was retiring from Congress.
Split into simpler sentences: After his election as Mayor, he served the city until 1990. Following his term as Mayor, Filiberto ran in the 1990 Republican Primary for the 2nd Congressional District seat in Florida then held by Bill Nelson, who was retiring from Congress.