SQL> create table T ( x int );

Table created.

SQL> create or replace trigger TRG
  2  before insert on T
  3  for each row
  4  declare
  5    p int;
  6  begin
  7    select :new.x into p from dual;
  8    dbms_lock.sleep(30);
  9  end;
 10  /

Trigger created.

SQL>
SQL> insert into T values (10);

[will take 30 seconds to run]

SQL> select owner, object_name
  2  from   dba_objects
  3  where  object_id =
  4    ( select PLSQL_ENTRY_OBJECT_ID
  5      from   v$session
  6      where  sid = 256 );   -- 256, the sid for session 1

OWNER                          OBJECT_NAME
------------------------------ -----------------
SCOTT                          TRG