By adding another 3rd interval on top of an 11th chord, various types of 13th chords can be created. Once again depending on the 3rd and 7th of the chord, you can create major, minor and dominant 13th chords.
The chord shown below is a C dominant 13th (C13). By flattening the 3rd of the chord it could be changed to a minor 13th chord (Cm13). By raising the 7th it could be changed to a major 13th (CMaj13).