Charles McNary was appointed to the Senate in 1917 after the death of Harry Lane. McNary ran for the full term beginning March 4, 1919, but did not run in the simultaneous special election to fill the remainder of Lane's term expiring on March 4, 1919. Fredrick Mulkey won the special election and replaced McNary on November 6, 1918. Mulkey, however, resigned on December 17, 1918 and McNary was reappointed to serve the remaining three months of the term.
Source for Popular Vote data: Oregon Secretary of State. Blue Book and Official Directory 1919-1920, Oregon Secretary of State (https://babel.hathitrust.org/cgi/pt?id=inu.30000091790844&view=page&seq=158) (accessed 15 Sep 2023)