For each party, return its theme and the name of its host.
SELECT T3.Party_Theme ,  T2.Name FROM party_host AS T1 JOIN HOST AS T2 ON T1.Host_ID  =  T2.Host_ID JOIN party AS T3 ON T1.Party_ID  =  T3.Party_ID
for each party refers to a need for grouping or selecting distinct records of parties; return its theme and the name of its host refers to selecting Party_Theme from party table and Name from host table; joining is required between party_host, host, and party tables on Host_ID and Party_ID to relate the host to their respective parties;