The vice president becomes President if the President dies or is removed from office . There are also procedures by which the vice-president can temporarily assume the duties of president, either voluntarily or involuntarily.
Even though the question is who takes over the v.p. and not what the president pro tempore takes over
The Pro Tempore Currently, Robert C. Byrd
If the Vice President is absent from the Senate, the President pro tempore or another designated senator takes over the role of presiding officer. The President pro tempore is typically the senior member of the majority party and is elected by the Senate. This individual assumes the responsibilities of the Vice President in leading Senate sessions and maintaining order.
In a play the understudy takes over when the actor is absent for any reason. For example, when the actor is ill.
the President pro tempore
The 'President Pro Tempore' is the President of the Senate, when the Vice President of the United States is absent.
The Vice President. If the Vice President is absent, the Secretary runs the meeting.
The speaker of the house takes over(:
If the vice-president is absent, some other senator, such are the pro tempore, presides over the Senate.
The vice president
The Vice President
The vice president