Supporting band's skill in German (6)
I believe the answer is:
garter
'supporting band's' is the definition.
(band giving support to stockings)
'skill in german' is the wordplay.
'skill' becomes 'art' (both can mean a talent).
'in' indicates putting letters inside.
'german' becomes 'ger' (abbreviation).
'art' going into 'ger' is 'GARTER'.
(Other definitions for garter that I've seen before include "Stocking supporter" , "Band involved in hold-up" , "Band holding up sock" , "- Belt; - snake; - stitch" , "It holds a stocking up" .)