Sen. Charles McC. Mathias Jr. (R-Md.) urged President Carter yesterday to support full voting representation in Congress for the District of Columbia calling it a domestic version of the President's global campaign for human rights.

"What we need from (Carter) . . . is a strong voice of support" for a constitutional amendment to give the District full membership in both the Senate and House, Mathias said in a statement submitted to a House Judiciary subcommittee hearing on the voting proposal.

Rep. Don Edwards (D-Calif.), chairman of the subcommittee, said there has been no word from the White House on when or whether the President will announce his position. Last February, Carter endorsed D.C. representation in the House but expresed doubt about the Senate.

Yesterday's hearing was the second of three scheduled on the measure, with the last one set for next Wednesday. Support for the pending measure was voiced yesterday by Mayor Walter E. Washington and by Clarence Mitchell, director of the Washington bureau of the National Association for the Advancement of Colored People.

Also testifying was a 16-year-old Gonzaga High School student, David Junious, who told the lawmakers he was puzzled by the lack of voting representation.

Rep. Ray Thornton (D-Ark.) suggested in testimony that the District be given back to Maryland for the limited purpose. By this process, he said, District residents would be assured of voting for at least two members of the House and would join in voting for the two Maryland senators.

What is now the District of Columbia was part of Maryland until 1790. District residents voted in Maryland elections until 1800.