CREATE TABLE "table1_1341930_38" (
  "district" text,
  "incumbent" text,
  "party" text,
  "first_elected" real,
  "result" text,
  "candidates" text
);

Question: How many incumbents come from alvin bush's district?
SQL: SELECT COUNT("candidates") FROM "table1_1341930_38" WHERE "incumbent"='Alvin Bush';