Use a function which will exactly tell Oracle what you want. Such as
select * from emp
where createdate between to_date('03-07-10', 'dd-mm-yy') and ...
Because, Oracle is probably confused (and so am I). What is '03-07-10'? Is it July 3rd 2010? Is it October 7th 2003? Is it ...?
Besides, '03-07-10' is just a string (CHARACTER!), not a date (although it might look as one to you). Therefore, NEVER rely on possible implicit datatype conversion. ALWAYS use TO_DATE when dealing with dates.