CREATE TABLE table_20921 ("Country" TEXT, "Region" TEXT, "Joined OPEC" FLOAT, "Population  ( July 2012 ) " FLOAT, "Area  ( km\\u00b2 ) " FLOAT, "Production  (  bbl /day ) " TEXT)

When did the country that produced 1,213,000 (21st) bbl/day join Opec?
SELECT "Joined OPEC" FROM table_20921 WHERE "Production ( bbl /day)" = '1,213,000 (21st)'
SELECT "Joined OPEC" FROM "table_20921" WHERE "Production ( bbl /day)" = '1,213,000 (21st)'