This question is for any criminal attorney who can help me?

I was wrongly bullied into taking a plea-bargain in 1996 and I have had a complete total clean record since then and i want to apply for either a pardon or to have my record completely expunged an di need to know how i go about doing that or if it can even be done. if you e-mail me i will give you the details of the case. btw i live in ohio