CREATE TABLE table_18612 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

How many candidates were in the election featuring brooks hays (d) unopposed?
SELECT COUNT("First elected") FROM table_18612 WHERE "Candidates" = 'Brooks Hays (D) Unopposed'
SELECT COUNT("First elected") FROM "table_18612" WHERE "Candidates" = 'Brooks Hays (D) Unopposed'