SQL> create table a ( col1 number, col2 number, col3 varchar2(10));

Table created.

SQL> create table b ( col1 number, col2 number, col3 varchar2(10));

Table created.
SQL> ed
Wrote file afiedt.buf

  1  create or replace trigger a_hist
  2  after insert or delete
  3  on a
  4  for each row
  5  begin
  6  if inserting then
  7  insert into b values (:new.col1,:new.col2,:new.col3);
  8  elsif deleting then
  9  insert into b values (:old.col1,:old.col2,:old.col3);
 10  end if;
 11* end;
SQL> /

Trigger created.

SQL> insert into a values (1,10,'aaa');

1 row created.

SQL> insert into a values (2,20,'bbb');

1 row created.

SQL> delete a where col1 = 2;

1 row deleted.

SQL> select * from a;

      COL1       COL2 COL3
---------- ---------- ----------
         1         10 aaa

SQL> select * from b;

      COL1       COL2 COL3
---------- ---------- ----------
         1         10 aaa
         2         20 bbb
         2         20 bbb

SQL>