What is the head of government for Don Stephen Senanayake?
CREATE TABLE "list_of_foreign_ministers" (
  "name" text,
  "party" text,
  "tenure" text,
  "head_s_of_government" text,
  "ministerial_title" text
);
SELECT "head_s_of_government" FROM "list_of_foreign_ministers" WHERE "name"='don stephen senanayake';