SELECT *
  FROM (SELECT D.NAME AS MAH_ADI, COUNT(*) AS BINA_ADET
          FROM BUILDINGS B, DISTRICTS D
         WHERE sde.st_intersects(sde.st_centroid(B.SHAPE), D.SHAPE) = 1
         GROUP BY D.NAME
         ORDER BY BINA_ADET DESC) A
WHERE ROWNUM <= 3