CREATE TABLE table_18645 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

What was the party that was frist elected in 1919?
SELECT "Party" FROM table_18645 WHERE "First elected" = '1919'
SELECT "Party" FROM "table_18645" WHERE "First elected" = '1919'