1787
Jefferson won the election in 1800 against John Adams, and was inaugurated on March 4, 1801.
Then the vice president-elect becomes president.
The vice-president becomes President if the president can not function.
Thomas Jefferson
The vice president would become the acting president.
If both die then the Speaker of the House becomes president
President pro tempore of the Senate becomes President.
The President is still the President if he or she is out of the country - it's only when he or she is INCAPACITATED that the Vice-President becomes (acting) President.
The New President Chooses a Replacement , (:
Death of a sitting president the Vice President becomes president, election, or by resignation and the Vice President again becomes president.
Vice President
The president 's choice (subject to the consent of both Houses of Congress)