who is the writer of the episode with prod.code 30-17
CREATE TABLE "table1_13403120_1" (
  "num" real,
  "title" text,
  "director" text,
  "writer_s" text,
  "originalairdate" text,
  "repeatairdate_s" text,
  "prod_code" text
);
SELECT "writer_s" FROM "table1_13403120_1" WHERE "prod_code"='30-17';