Complex sentence: Allen served as a Representative from Ohio from 1832 to 1834, when he lost a bid for re-election, and Senator from Ohio from 1837 to 1849, losing a bid for a third term in 1848.
Split into simpler sentences: Allen served as United States Representative from Ohio from 1832 to 1834, losing his bid for re-election. He served as United States Senator from Ohio from 1837 to 1849, losing a bid for a third term in 1848.