Complex sentence: He was elected Senate Minority Leader for the 68th Congress (1923-1925), and remained leader of Senate Democrats till his death, becoming Senate Majority Leader in 1933 when the Democrats became the majority.
Split into simpler sentences: He was elected Senate Minority Leader for the 68th Congress (1923-1925) and remained leader of Senate Democrats till his death. Robinson became Senate Majority Leader in 1933 when the Democrats became the majority.