CREATE TABLE table_203_756 (id NUMBER, "year" NUMBER, "title" CLOB, "role" CLOB, "network" CLOB, "notes" CLOB)

role played at least twice
SELECT "role" FROM table_203_756 GROUP BY "role" HAVING COUNT(*) >= 2
SELECT "role" FROM "table_203_756" GROUP BY "role" HAVING COUNT(*) >= 2