Composition by Prokofiev for old Russian leadership (6)
I believe the answer is:
troika
I believe this clue is a double definition.
'composition by prokofiev' is the first definition.
(a movement from Prokofiev's Lieutenant Kije)
'old russian leadership' is the second definition.
(term for various three-person Soviet leaderships)
'for' is the link.
(Other definitions for troika that I've seen before include "Russian horse-drawn vehicle" , "Group of three" , "3 hp vehicle" , "Russian three-horse carriage" , "Russian conveyance" .)