What is the percentage of the Labour Party on the Harris Poll
CREATE TABLE "opinion_poll_summary" (
  "party" text,
  "marplan" text,
  "gallup" text,
  "national_opinion_polls_nop" text,
  "opinion_research_centre_opc" text,
  "harris" text
);
SELECT "harris" FROM "opinion_poll_summary" WHERE "party"='Labour';