CREATE TABLE table_18537 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

what is the minimum number first elected to district louisiana 5?
SELECT MIN("First elected") FROM table_18537 WHERE "District" = 'Louisiana 5'
SELECT MIN("First elected") FROM "table_18537" WHERE "District" = 'Louisiana 5'