The Senate's elected leader, known as the president pro tempore, presides over the Senate in the absence of the Vice President. Typically he will cede this role to junior members who will practice the formal parliamentary procedure of the Senate.
The position is separate from the leaders of each party in the Senate, known as the Majority Leader and Minority Leader, and by custom is a senior member of the Senate.
the vp of the senate
The Senate is where the VP presides.
President of the Senate (The Vice President) Actually no one is 'in charge of' the Senate. If anyone has a responsibility to try to govern the Senate, it's the responsibility of the two leaders. Article 1 of the US Constitution says "The Vice President of the United States shall be President of the Senate, but shall have no vote, unless they be equally divided." This means that the VP would be the deciding vote were there to be a tie in votes, but is not 'in charge of' the Senate.
The President of the Senate (VP of US) votes to break ties.
The VP of the US chairs the Senate.
The Senate President Pro Tempore
The VP chairs the Senate and can vote if a tie-vote occurs. Therefore the party that the VP belongs to can pass legislation with only 50 votes.
He is the VP and not a voting member of the Senate, but he can vote in the event of a tie.
The VP is not a Senator. His job is to chair meetings. He can not vote unless there is a tie vote.
VP Joe Biden
majority leader
There is no Vice-president in that case. That office remains vacant and the duties of the Vice-president to preside over the Senate is then handled by the President pro tempore of the Senate.