The next senator to occupy 306 Hart Senate Office Building will be just the second.

It has been the office of Sen. Richard Lugar, R-Ind., whose Senate career ended with Thursday’s swearing-in ceremony for new senators. Lugar lost the GOP primary election to state Treasurer Richard Mourdock, who was defeated in the general election by Rep. Joe Donnelly, D-2nd.

Lugar “is the only senator to have occupied Hart 306,” spokesman Andy Fisher said this week in an email. “He was forced to move from his Dirksen (building) office when the Hart building opened in January 1983 – 30 years ago.”

Lugar at the time was starting the second of what would be six six-year terms, by far the longest career of any senator from Indiana. The Hart building was named for Sen. Philip Hart, D-Mich., who died in office in December 1976, not long after Lugar was first elected to the Senate.

Lugar’s final vote in the chamber on Tuesday – in favor of the American Taxpayer Relief Act, which extended income-tax cuts for most Americans – was the 13,067th of his career, Fisher said, ranking him 10th in the history of the Senate, which dates to 1789. Fisher noted that Lugar has served with all nine senators ahead of him in the number of votes cast.

The late Robert Byrd, a West Virginia Democrat, leads the list with 18,689 votes. With Lugar’s departure and the recent death of Hawaii Democrat Daniel Inouye, the only current senator in the top 10 is Vermont Democrat Patrick Leahy, who ranks seventh with 14,066 votes cast.

Fisher said Lugar compiled a 98.27 percent voting attendance record.