check time of specific parts of sp's

SELECT  requests.session_id,
        requests.status,
        requests.command,
        requests.statement_start_offset,
        requests.statement_end_offset,
        requests.total_elapsed_time,
        SUBSTRING(details.text,
                  requests.statement_start_offset / 2,
                  (requests.statement_end_offset - requests.statement_start_offset) / 2)  as problem
FROM    sys.dm_exec_requests requests
CROSS APPLY sys.dm_exec_sql_text (requests.plan_handle) details
WHERE   requests.session_id > 20
ORDER BY total_elapsed_time DESC