Complex sentence: Only Conrad has filed as a Dem-NPLer, and the only Republican to have filed by the deadline is Anderson town councilman and farmer Dwight Grotberg, who has not previously run a statewide political campaign.
Split into simpler sentences: Only Conrad has filed as a Dem-NPLer, and the only Republican to have filed by the deadline is farmer Dwight Grotberg. Dwight has not previously run a statewide political campaign.