CREATE TABLE table_20312 ("Series" CLOB, "Episodes" FLOAT, "Series premiere" CLOB, "Series finale" CLOB, "Region 1" CLOB, "Region 2" CLOB, "Region 4" CLOB)

Which episode was N/A in region 1
SELECT "Episodes" FROM table_20312 WHERE "Region 1" = 'N/A'
SELECT "Episodes" FROM "table_20312" WHERE "Region 1" = 'N/A'