Complex sentence: He was an assistant U.S. Attorney of the District of Vermont from 1940 to 1954, and was a civilian aide for the U.S. Secretary of the Army from 1962 to 1966.
Split into simpler sentences: He was an assistant U.S. Attorney for the District of Vermont from 1940 to 1954. Leddy was a civilian aide for the U.S. Secretary of the Army from 1962 to 1966.