declare @t table (id int, debit int, credit int)
insert into @t values
(1 , 1500 , NULL),
(2 , NULL	, 800),	
(3 , 200 ,NULL),
(4 , NULL	,1500),
(5 , 1300 ,NULL),
(6 , NULL ,500),	
(7 , 800 , NULL),
(8 , 938	,NULL)

;with cte as (
	select 
		*
		,all_credit		=sum(credit)over()
		,cur_debit		=sum(debit)over(order by id)   
	from @t
)
select top 1 
	* 
from cte 
where all_credit-cur_debit<0
order by /* ?? all_credit-cur_debit desc, */ id 

;with cte as (
	select 
		t1.*
		,all_credit		=sum(t1.credit)over()
--		,cur_debit		=sum(debit)over(order by id)
		,x.cur_debit   
	from @t t1
	outer apply(select sum(t2.debit) as cur_debit from @t t2 where t2.id<=t1.id) x
)
select top 1 
	* 
from cte 
where all_credit-cur_debit<0
order by /* ?? all_credit-cur_debit desc, */ id