On the surface, there's nothing in a piece of stage scenery (6)
I believe the answer is:
afloat
'on the surface' is the definition.
(I've seen this before)
'nothing in a piece of stage scenery' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'in' is an insertion indicator.
'piece of stage scenery' becomes 'flat' (I can't justify this - if you can you should give a lot more credence to this answer).
'a'+'flat'='aflat'
'o' going into 'aflat' is 'AFLOAT'.
'there's' is the link.
Can you help me to learn more?
(Other definitions for afloat that I've seen before include "Bobbing along?" , "Buoyed" , "Out of debt; at sea" , "Still solvent" , "Aboard ship" .)