CREATE TABLE table_41370 ("Party" CLOB, "Marplan" CLOB, "Gallup" CLOB, "National Opinion Polls  ( NOP ) " CLOB, "Opinion Research Centre  ( OPC ) " CLOB, "Harris" CLOB)

What is Opinion Research Centre (OPC), when Party is Conservative?
SELECT "Opinion Research Centre (OPC)" FROM table_41370 WHERE "Party" = 'conservative'
SELECT "Opinion Research Centre (OPC)" FROM "table_41370" WHERE "Party" = 'conservative'