CREATE TABLE table_18185 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

what being the minimum first elected with district being washington 7
SELECT MIN("First elected") FROM table_18185 WHERE "District" = 'Washington 7'
SELECT MIN("First elected") FROM "table_18185" WHERE "District" = 'Washington 7'