The Spanish last in the river (4)
I believe the answer is:
elbe
'river' is the definition.
(river in Germany)
'the spanish last in' is the wordplay.
'the spanish' becomes 'el' ('the' in Spanish).
'last in' becomes 'be' (I can't justify this - if you can you should believe this answer much more).
'el'+'be'='ELBE'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for elbe that I've seen before include "European river" , "Current" , "River flowing through Dresden and Hamburg" , "A major German river" , "It flows through Germany" .)