How many candidates won the election in the district whose incumbent is Bud Shuster?
CREATE TABLE "table1_1341604_39" (
  "district" text,
  "incumbent" text,
  "party" text,
  "first_elected" real,
  "result" text,
  "candidates" text
);
SELECT COUNT("candidates") FROM "table1_1341604_39" WHERE "incumbent"='Bud Shuster';