CREATE TABLE table_18598 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

How many partys have a candidate first elected in 1923?
SELECT COUNT("Party") FROM table_18598 WHERE "First elected" = '1923'
SELECT COUNT("Party") FROM "table_18598" WHERE "First elected" = '1923'