This depends on the organization/country. See related questions.
US: Ronald Reagan
Ronald Reagan was the 41st President of the United States from 1981 January 20 to 1989 January 20.
James Monroe, the 5th president of the US was president during the Missouri Compromise.
This happened during World War II after the Japanese attacked the US base in Hawaii when Franklin Roosevelt was president.
James Madison was the president of the United States throughout the entirety of the war of 1812. He served as president from 1809-1817.
Lyndon Johnson.
Eisenhower
The US president during WW2 was Franklin D. Roosevelt.
Abraham Lincoln was president during the US Civil War.
James Monroe, the 5th president of the US was president during the Missouri Compromise.
James Knox Polk was the US president during the Mexican War.
who was the us president at the time of the battle of France
the president during ww1 was Wilson
I think Jimmy Carter was US President at the time.
who replaces the president of the US senate in his absences
Clinton
Woodrow Wilson was the US president during WW I.
The US president was James Madison
President McKinely