Try this:
ALTER procedure [dbo].[GetSupplierToVendorDetails]
@did varchar(50)
as
begin
SELECT ROW_NUMBER() OVER(ORDER BY stvd.SrNo) AS SrNo, stvd.Product_Id, p.Product_Name, stvd.Quantity, vcd.Quantity AS DispatchedQty
FROM Tbl_Dispatch_SupplierToVendor_Details AS stvd INNER JOIN
Tbl_ProductMaster AS p ON stvd.Product_Id = p.Product_Id INNER JOIN
Tbl_Dispatch_VendorToClient AS vc ON stvd.SupplierToVendor_Id = vc.SupplierToVendor_Id INNER JOIN
Tbl_Dispatch_VendorToClient_Details AS vcd ON vcd.VendorToClient_Id = vc.VendorToClient_Id and
vcd.Product_id=stvd.Product_Id
WHERE (stvd.SupplierToVendor_Id = @did)