Somewhat dull university magazine is supported by one local (13)
I believe the answer is:
unimaginative
'somewhat dull' is the definition.
(I've seen this before)
'university magazine is supported by one local' is the wordplay.
'university magazine' becomes 'imagi' (I can't justify this - if you can you should believe this answer much more).
'is supported by' says to put letters next to each other (in a down clue, some letters hold up others).
'one' becomes 'un' (northern English dialect form of 'one').
'local' becomes 'native' (similar in meaning).
'imagi' put after 'un' is 'unimagi'.
'unimagi'+'native'='UNIMAGINATIVE'
Can you help me to learn more?
(Other definitions for unimaginative that I've seen before include "Lacking invention" , "Mentally rather dull" , "Lacking in mental creativity" , "Stolid, somewhat dull" .)