Entity FrameWork Query

Question

Serial Number	CHECK_NUMBER	CHECK_VERSION	ROUTING_NUMBER	TRANSACTION_SEQUENCE
1	09172113334652298482	New	615114379	1
2	03346522984829172113	New	679151143	2
3	02113391784823465229	New	619511437	3
4	09172113334652298482	Old	615114379	2
5	03346522984829172113	Old	679151143	3
6	02113391784823465229	Old	619511437	4

For My  Entity FrameWork, in the For Loop

While working Evaluating, serial number 4 5 and 6

I should get the previous Tansaction(Transaction Sequence - 1) row

Ex: for SerialNumber 4, the previuos transaction is 1, same way for 5 its 2 and for 6 its 3

I tried below, it did not work

var previousTransactions = transactions
    .Where(pt => pt.Check_Number == t. Check_Number
    //&& pt.Check_Version == t. pt.Check_Version
    && pt.Transaction_Sequence == Transaction_Sequence).FirstOrDefault();
    //.OrderByDescending(pt => pt.Sequence_Number).FirstOrDefault());
    .Distinct(new TransactionComparer());
}