Often here on IrI we members (even Admins) can not differentiate between Budget and Supplementary and Excess Demands for Grants and often terms latter as Supplementary Budget which is different than earlier two. Here any one can understand it by cliking:
THE BUDGETARY PROCESS
* Budget is presented to Lok Sabha in two parts, namely, the Railway Budget pertaining to Railway Finance and the General Budget which gives an overall picture of the financial position of the Government of India, excluding the Railways.
**...
more...

Supplementary and Excess Demands for Grants
If the amount authorised to be expended for a particular service for the current financial year is found to be insufficient for the purpose of that year or when a need has arisen during the current financial year for supplementary or additional expenditure upon some ‘new service’ not contemplated in the Budget for that year the President causes to be laid before both the Houses of Parliament another statement showing the estimated amount of that expenditure.
If any money has been spent on any service during a financial year in excess of the amount granted or the service for that year, the President causes to be presented to Lok Sabha a demand for such excess. All cases involving such excesses are brought to the notice of Parliament by the Comptroller and Auditor General through his report on the Appropriation Accounts. The excesses are then examined by the Public Accounts Committee which makes recommendations regarding their regularisation in its report to the House.
The Supplementary Demands for Grants are presented to and passed by the House before the end of the financial year while the demands for excess grants are made after the expenditure has actually been incurred and after the financial year to which it relates, has expired.
Copies of the Books of Demands for Supplementary or Excess Grants, received from the Ministry of Finance, are made available to members from the Publications Counter after the presentation of such demands.