CREATE TABLE table_718 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

What year was ike skelton first elected?
SELECT MIN("First elected") FROM table_718 WHERE "Incumbent" = 'Ike Skelton'
SELECT MIN("First elected") FROM "table_718" WHERE "Incumbent" = 'Ike Skelton'