Watch display by pioneering German band (3,8)
I believe the answer is:
led zeppelin
'band' is the definition.
(I've seen this before)
'watch display by pioneering german' is the wordplay.
'watch display' becomes 'LED' (Light Emitting Diode - used in watch screens).
'by' means one lot of letters go next to another.
'pioneering german' becomes 'zeppelin' (German inventor Count Ferdinand von Zeppelin).
'led'+'zeppelin'='LED ZEPPELIN'
(Other definitions for led zeppelin that I've seen before include "Band" , "English heavy metal group, founded 1968" , "Rock group with vocalist Robert Plant" .)