The D flat major thirteenth chord is a 6-note chord consisting of the notes Db, F, Ab, C, Eb and Bb.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Dbmaj13.
Interactive piano diagram for the D flat major thirteenth chord
Chords that are a subset of Dbmaj13. These contain less notes but all of them are included in Dbmaj13.