Yes, the second chord would be a passing chord in Db
Here is a another example, using the chords you posted (I modified the 1st and 2nd chord just a little). Most times you won't go from Bb to A and then back to Bb in the bass and use a passing chord, although you can. Example using Ab to (A passing) to Bb in Bass.
IN THE KEY OF Db
LH/RH
Ab/Ab C Db F
A/A Db Eb Ab PASSING TONE ?????????
Bb/F Bb Db