CREATE TABLE table_18283 ("District" CLOB, "Incumbent" CLOB, "Party" CLOB, "First elected" FLOAT, "Result" CLOB, "Candidates" CLOB)

To which party does Robert W. Edgar belong?
SELECT "Party" FROM table_18283 WHERE "Incumbent" = 'Robert W. Edgar'
SELECT "Party" FROM "table_18283" WHERE "Incumbent" = 'Robert W. Edgar'