CREATE TABLE table_18370 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

How many incumbent candidates in the election featuring sam m. gibbons (d) unopposed?
SELECT COUNT("Incumbent") FROM table_18370 WHERE "Candidates" = 'Sam M. Gibbons (D) Unopposed'
SELECT COUNT("Incumbent") FROM "table_18370" WHERE "Candidates" = 'Sam M. Gibbons (D) Unopposed'