A thirteenth chord is created by adding a 13th degree to any dominant 11th chord. For example, a C13 chord contains the notes C, E, G, Bb, D, F and A (1, 3, 5, b7, 9, 11 and 13). The 11th degree is usually omitted because of its clash with the 13rd degree.
F13
F#13
G13
Ab13
A13
C13
Db13
D13
Eb13
E13
Bb13
B13