CREATE TABLE table_18248 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

Who is the incumbent that is listed with the candidates listed as marilyn lloyd (d) 57.4% harold w. coker (r) 42.6%?
SELECT "Incumbent" FROM table_18248 WHERE "Candidates" = 'Marilyn Lloyd (D) 57.4% Harold W. Coker (R) 42.6%'
SELECT "Incumbent" FROM "table_18248" WHERE "Candidates" = 'Marilyn Lloyd (D) 57.4% Harold W. Coker (R) 42.6%'