CREATE TABLE table_3609 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" TEXT, "Result" TEXT, "Candidates" TEXT)

Who were the incumbent(s) in the election featuring john murray (dr) 50.4% george denison (dr) 49.6% with a result of a retired democratic-republican hold?
SELECT "Incumbent" FROM table_3609 WHERE "Candidates" = 'John Murray (DR) 50.4% George Denison (DR) 49.6%' AND "Result" = 'Retired Democratic-Republican hold'
SELECT "Incumbent" FROM "table_3609" WHERE "Candidates" = 'John Murray (DR) 50.4% George Denison (DR) 49.6%' AND "Result" = 'Retired Democratic-Republican hold'