I've checked their website, but nothing appears related to membership checking. Typically, when you've applied for membership, an ID was given you and all the necessary papers that prove you are a member of OWWA. You should check those papers. Secondly, their download section on the official website doesn't have a program or something to manually input your data to check the membership, therefore you have to contact them through the proper channels.
Use the following link to reach the contact page then locate your zone where you applied to reveal the contact information: http://www.owwa.gov.ph/?q=content/contact-us