CREATE TABLE "table1_13403120_1" (
  "num" real,
  "title" text,
  "director" text,
  "writer_s" text,
  "originalairdate" text,
  "repeatairdate_s" text,
  "prod_code" text
);

Question: What is the original date of the repeat air date of 26/01/1969?
SQL: SELECT "originalairdate" FROM "table1_13403120_1" WHERE "repeatairdate_s"='26/01/1969';

Question: What is the repeat date of the episode that aired 22/12/1968?
SQL: SELECT "repeatairdate_s" FROM "table1_13403120_1" WHERE "originalairdate"='22/12/1968';

Question: who is the writer of the episode with prod.code 30-17
SQL: SELECT "writer_s" FROM "table1_13403120_1" WHERE "prod_code"='30-17';

Question: what is the prod.code of the episode with original air date 01/12/1968?
SQL: SELECT COUNT("prod_code") FROM "table1_13403120_1" WHERE "originalairdate"='01/12/1968';