CREATE TABLE table_55077 ("NGC number" FLOAT, "Object type" TEXT, "Constellation" TEXT, "Right ascension  (  J2000  ) " TEXT, "Declination  (  J2000  ) " TEXT)

what is the ngc number when the constellation is leo and the declination (j2000) is 42 13 ?
SELECT AVG("NGC number") FROM table_55077 WHERE "Constellation" = 'leo' AND "Declination ( J2000 )" = '°42′13″'
SELECT AVG("NGC number") FROM "table_55077" WHERE "Constellation" = 'leo' AND "Declination ( J2000 )" = '°42′13″'