Who sits behind the President, when there is no VP

Bit obscure, but I caught the movie “The Contender” which culminated in the President delivering a speech before the joint houses of Congress, much in the same way that he delivers a State of the Union speech every year.

Well, in the plot of the movie, there was no Vice-President, his having passed away, so I was left to wonder who was sitting behind him during his speech. Obviously, one of the men was the Speaker of the House, but the other wasn’t identified, and as that chair usually belongs to the leader of the Senate, it raised the question, who gets to take the VP’s seat if there is no VP. Senate Majority Leader perhaps?

President pro tempore of the Senate, I believe. Think that might be Strom Thurmond at the moment, but it’s not nearly as important a position as majority leader.