CREATE TABLE table_18464 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Result" TEXT, "Candidates" TEXT)

Name the number of party with the incubent james william trimble
SELECT COUNT("Party") FROM table_18464 WHERE "Incumbent" = 'James William Trimble'
SELECT COUNT("Party") FROM "table_18464" WHERE "Incumbent" = 'James William Trimble'