CREATE TABLE "singles_performances_5_3" (
  "edition" text,
  "round" text,
  "date" text,
  "against" text,
  "surface" text,
  "opponent" text,
  "win_lose" text,
  "result" text
);

Question: In what edition is Ungur's opponent David Nalbandian?
SQL: SELECT "edition" FROM "singles_performances_5_3" WHERE "opponent"='David Nalbandian';

Question: When was the win/lose lose and the round a play-off?
SQL: SELECT "date" FROM "singles_performances_5_3" WHERE "win_lose"='Lose' AND "round"='Play-off';

Question: In what round did he play against Sergiy Stakhovsky?
SQL: SELECT "round" FROM "singles_performances_5_3" WHERE "opponent"='Sergiy Stakhovsky';