Who played in the men's singles during the tournament where Ragna Ingolfsdottir played in the women's singles?
CREATE TABLE "previous_winners" (
  "year" real,
  "men_s_singles" text,
  "women_s_singles" text,
  "men_s_doubles" text,
  "women_s_doubles" text,
  "mixed_doubles" text
);
SELECT "men_s_singles" FROM "previous_winners" WHERE "women_s_singles"='ragna ingolfsdottir';