Question: What is the original date of the repeat air date of 26/01/1969?
SQL: SELECT "Originalairdate" FROM "1-13403120-1" 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 "1-13403120-1" WHERE "Originalairdate" = '22/12/1968';

Question: who is the writer of the episode with prod.code 30-17
SQL: SELECT "Writer(s)" FROM "1-13403120-1" 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 "1-13403120-1" WHERE "Originalairdate" = '01/12/1968';