Sen. Charles McC. Mathias Jr. (R-Md.) thinks 13 will be his lucky number.

Today he announced that for the 13th and final time he has introduced legislation to have Congress reimburse the city of Frederick for a $200,000 ransom it paid to the Confederate Army to save federal supplies stored here during the Civil War.

Mathias, who is from Frederick and still owns a home here, told reporters assembled at city hall that he is "confident" that with "renewed personal effort," the 13th time will be the charm.

The controversy over reimbursement stems from a 1864 incident in which Confederate Gen. Jubal Early and more than 10,000 troops stormed into Frederick and demanded that the city, which had $1.5 million worth of military and medical supplies for the union army stored at local warehouses, pay $200,000 in ransom or be burned. Leaders of the city of 8,000 residents, noting that the nearby city of Chambersburg, Pa., was burned to the ground after refusing a similar demand, decided to pay. The ransom, funded by borrowing from local banks and by issuing bonds, was not fully paid off until 1970.

The $200,000 debt amounted to 10 percent of the city's tax base at the time, said Frederick Mayor Ronald Young. A similar debt today would amount to more than $30 million, he noted.

It is a debt that Frederick has not forgotten. Since 1889, bills have been introduced in Congress demanding that the federal government pay up.

Mathias, who began his quixotic crusade for reimbursement as a freshman representative in 1961, said he did not think that his decision to retire after the 1986 elections, would influence members of Congress to pass the legislation as a personal favor to him. "The bill stands on its own merits," he said. "It's a justified claim that is supported by the historical facts."

In a prepared statement, Mathias said, "History records that many cities suffered damage during the Civil War, yet few incurred such a prodigious debt as that of Frederick. Frederick sacrificed money it did not have in order to defend federal supplies. I hope that Congress will finally see that justice is served and this city will receive its long overdue compensation."

Mathias said legislation to repay the city has been introduced by various Maryland representatives upwards of 50 times. A number of bills have been passed by either the House of Representatives or the Senate, he said, but none has been passed by both. "The printing costs alone are worth passing the bill and settling the account," he quipped.

While no one seems to be adamantly opposed to the bill, said Mathias staff member Randolph Dove, "it is not a priority item for most members."

The city of Frederick, meanwhile, believes that the patriotic action of their ancestors has been overlooked far too long.

"It's a question of fairness," said Mayor Young. "The city laid out money to save $1.5 million in federal supplies, and in the process, helped saved Washington from being invaded. We didn't finish paying off the debt for more than 100 years. That was money that could have been used for city projects and was never able to have been used in that way.

"This is our best and maybe our last shot" at getting the money, said Young. "Obviously it's going to be difficult for anyone else to pick up the project with the same enthusiasm and knowledge that Sen. Mathias has.

"It's never too late for justice," he added.