The DUI conviction will be made available to the probation department and the judge in your assault case, but it may or may not affect it given that it was a year ago. A prior conviction can affect the outcome of sentencing for your simple assault charge (assuming you plead or are found guilty at trial to this offense) as Judges and the Probation department, and even your sentencing guidelines if applicable, takes into account prior criminal convictions when issuing a new sentence on new charges such as the assault case. However, the Judge also has the authority to still sentence you without penalizing you for the prior conviction as well if the Judge so chooses.