Pass by il Duomo regularly providing refuge (6)
I believe the answer is:
asylum
'refuge' is the definition.
('asylum' can be a synonym of 'refuge')
'pass by il duomo regularly' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'pass'+'by'+'il'+'duomo'='passbyilduomo'
The alternating letters of 'passbyilduomo' are 'ASYLUM'.
'providing' is the link.
(Other definitions for asylum that I've seen before include "Refuge or home for mentally ill" , "find sanctuary there" , "hostel" , "Place of shelter or refuge" , "Refugee's protection" .)