Κατὰ δὲ ἑορτὴν εἰώθει ὁ ἡγεμὼν ἀπολύειν ἕνα τῷ ὄχλῳ δέσμιον, ὃν ἤθελον.

1. Κατὰ
   According to
2. δὲ
   but
   and
3. ἑορτὴν
   feast
   festival
4. εἰώθει
   he was accustomed
   was accustomed
5. ὁ
   the
6. ἡγεμὼν
   leader
7. ἀπολύειν
   to release
8. ἕνα
   one
9. τῷ
   the
   to the
10. ὄχλῳ
    crowd
11. δέσμιον
    prisoner
12.  
    ,
     
13. ὃν
    which
    whom, being
14. ἤθελον
    they wanted
    they were willing, were willing
15.  
    .
     

But according to the feast, the leader was accustomed to release one prisoner to the crowd, whom they wanted.