Yes. The Federal Wiretap Act and its Ohio counterpart require the police to obtain a wiretap warrant before listening to your phone conversations.
The warrant must be supported by a probable cause as well as a showing of necessity, meaning that the police have exhausted all other investigative methods. There are also restrictions on how long they can listen to your conversations if criminal activity is not being discussed.
If you have questions regarding any types of police procedures, call experienced Criminal Lawyer Mulligan & Associates at 937-228-9790 for a free consultation.