Dynamic Filter for Reporting

I have a field where we put in the phone number of the lead source that the lead came from and would like to be able to create a report where I can dynamically filter based on the lead source that it came from. When I go to the report options to select the option as a dynamic filter it is not showing up for me to select, I have my other items but not this one. How do I make this show up in the dynamic filters? I currently have it formatted as a phone number.

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Benjamin Brooks
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