Which nationality has a split in the 50m of 29.51?
CREATE TABLE "final" (
  "place" real,
  "lane" real,
  "name" text,
  "nationality" text,
  "50m_split" real,
  "100m_split" text,
  "150m_split" text,
  "time" text
);
SELECT "nationality" FROM "final" WHERE "50m_split"=29.51;