CREATE TABLE table_55922 ("NGC number" FLOAT, "Object type" TEXT, "Constellation" TEXT, "Right ascension  (  J2000  ) " TEXT, "Declination  (  J2000  ) " TEXT, "Apparent magnitude" FLOAT)

what is the right ascension (j2000) when the apparent magnitude is 13?
SELECT "Right ascension ( J2000 )" FROM table_55922 WHERE "Apparent magnitude" = '13'
SELECT "Right ascension ( J2000 )" FROM "table_55922" WHERE "Apparent magnitude" = '13'