This should do it.
SELECT Marks, QPName, Class, BthNo, CONVERT(DATETIME, Batchdate, 105) AS Batchdate, Attender
FROM STUDDET S,Batch B where S.BthId = B.BthId and S.StudId = '252'
Basically, we are converting the date into Italian format (105) with the century specified. If you didn't want the century in there, you'd just use 5 instead.