create or replace type lst_vc2 is table of varchar2(4000);
/

DECLARE
  v1 lst_vc2:=lst_vc2('01','02','03','04','05','06','07');
  v2 lst_vc2:=lst_vc2('03');
  v3 VARCHAR2(20);
BEGIN
  SELECT res
  INTO v3
  FROM
    (SELECT lag(column_value)over(order by column_value) res
    FROM TABLE(CAST (v1 AS lst_vc2))
    WHERE column_value='04'
    );
  dbms_output.put_line('count='||v3);
  v1.delete;
  v2.delete;
END;
/

SQL> with data as (select level nb from dual connect by level<=5)
  2  select prev_value
  3  from (select nb, lag(nb) over (order by nb) prev_value from data)
  4  where nb= 4
  5  /
PREV_VALUE
----------
         3