Just in case there are spaces in the middle name or even periods (which may be valid since the user might have just entered a middle initial with a period), you can add those characters to the query provided by visakh16:
SELECT middlename FROM pro WHERE middlename LIKE '%[^A-Za-z .]%'
But if you just want to search for "/", you can do it this way:
SELECT middlename FROM pro WHERE middlename like '%/%'