Choosed wrong assessment yr while paying self assessment

Assessment yr 09-10 was my first time i paid & file any Tax. I have filed the return on 30/07/09 online & have got the acknowledge for it. For this i have paid self assessment tax of about Rs.3690 on 29/07/09 but while paying it online by mistake i choose the assessment yr 08-09 instead of 09-10(thinking its as FY).
What should i do now ?  Should i leave it as it is since its my first return or will it create issue later? How to I rectify it?

Please let me know if you dn't understand my query or pls advise on above. Many thanks