Eleven candidates - five Independents, four D.C. Statehood Party members, a Republican and a U.S. Labor Party representative - filed nominating petitions by yesterday's deadline to enter the special July 19 election to fill the at-large City Council seat left vacant by the death of Julius Hobson Sr.

Democrats, who vastly outnumber all other political party members combined in the city, are barred from running in the election since they already occupy the maximum of two at-large Council seats permitted under the D.C. home rule charter.

Marion Barry, a key Democratic member of the City Council, however, yesterday endorsed Hilda mason, a Statehood Party member who was appointed recently by her fellow party members to fill Hobson's seat until the special election.

Hobson, the Statehood Party founder, died March 23 after serving less than a year of his four-year team.

Barry, who served with Mason when both were D.C. School Board members, said although they belong to different parties, he was supporting her because of her "continued effort to improve the quality of life for the citizens of the District of Columbia."

Those filing petitions before yesterday's 5 p.m. deadline included Mason, of 1459 Roxanna Rd. NW, and three other Statehood Party members, Leo F. Murray, of 1435 newton St. NW; Frank Sewell, of 2324 Irving St. NW, and Naomi T. Van Der Jagt, 1524 F St. Nw.

Independent candidates are former School Supt. Babarba A. Sizemore, of 1629 Columbia Rd. NW; former TV reporter Susan Truitt, of 3109 34th St. NW; Wade Jefferson, of 438 19th St. NE; James Clark, of 6445 Luzon Ave. NW, and Richard Clark, of 7509 14th St. NW.

The two other candidates are Republican Paul Hays, of 310 South Carolina Ave. SE, and U.S. Labor Party representative Susan Pennington, of 1650 harvard St. NW.

All D.C. registered voters are eligible to vote in the July 19 election. Although these candidates hav filed their petitions, they will not be certified to appear on the ballot until the D.C. Board of Elections and Ethics has vertified the signatures on their petitions.