Dresden's river (4)
I believe the answer is:
elbe
'dresden's river' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for elbe that I've seen before include "River rising in the Czech Republic and flowing into the North Sea" , "Dresden/Hamburg river" , "German banker" , "River flowing through Dresden and Hamburg" , "Current" .)