CREATE TABLE table_18588 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

In what year was Leo E. Allen first elected?
SELECT "First elected" FROM table_18588 WHERE "Incumbent" = 'Leo E. Allen'
SELECT "First elected" FROM "table_18588" WHERE "Incumbent" = 'Leo E. Allen'