Inaugurated in 1946, election in 1945.
The election for Roosevelt's fourth term was held 7 November 1944. POTUS candidates were FDR (D) and Thomas E. Dewey (R); VP choices were Harry S. Truman (D) and John W. Bricker (R). When votes were tabulated FDR got 53.4% (or 432 electoral votes) as opposed to 45.9% (or 99 electoral votes) for Dewey of 47,634,000 votes cast.
FDR was sworn-in for his fourth term on January 20, 1945. He died April 12, 1945. VP Truman went on to complete Roosevelt's unexpired fourth term. Truman was engaged in a three way race for POTUS in 1948, the election being held on November 2, 1948. When votes were tabulated HST (D) got 49.6% (or 303 electoral votes) as opposed to 45.9% (or 189 electoral votes) for Dewey (R) and 2.4% (or 39 electoral votes) for Strom Thurmond (Dixiecrat) of 47,346,000 votes cast.