CREATE TABLE table_18460 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

Name the candidates for l. mendel rivers
SELECT COUNT("Candidates") FROM table_18460 WHERE "Incumbent" = 'L. Mendel Rivers'
SELECT COUNT("Candidates") FROM "table_18460" WHERE "Incumbent" = 'L. Mendel Rivers'