What is the name of the speaker if the chief minister is M.G. Ramachandran?
CREATE TABLE "table1_23512864_4" (
  "election_year" real,
  "assembly" text,
  "winning_party_coalition" text,
  "chief_minister" text,
  "speaker" text
);
SELECT "speaker" FROM "table1_23512864_4" WHERE "chief_minister"='M.G. Ramachandran';