CREATE TABLE table_18128 ("District" TEXT, "Incumbent" TEXT, "Party" TEXT, "First elected" FLOAT, "Results" TEXT, "Candidates" TEXT)

How many candidates were there in the district won by Joe Hoeffel?
SELECT COUNT("Candidates") FROM table_18128 WHERE "Incumbent" = 'Joe Hoeffel'
SELECT COUNT("Candidates") FROM "table_18128" WHERE "Incumbent" = 'Joe Hoeffel'