what was the last time patient 31300 was prescribed pantoprazole and furosemide in 03/2103, at the same time?
select t1.startdate from ( select admissions.subject_id, prescriptions.startdate from prescriptions join admissions on prescriptions.hadm_id = admissions.hadm_id where prescriptions.drug = 'pantoprazole' and admissions.subject_id = 31300 and strftime('%y-%m',prescriptions.startdate) = '2103-03' ) as t1 join ( select admissions.subject_id, prescriptions.startdate from prescriptions join admissions on prescriptions.hadm_id = admissions.hadm_id where prescriptions.drug = 'furosemide' and admissions.subject_id = 31300 and strftime('%y-%m',prescriptions.startdate) = '2103-03' ) as t2 on t1.subject_id = t2.subject_id where datetime(t1.startdate) = datetime(t2.startdate) order by t1.startdate desc limit 1