Format for create query should be PropertyName=PropertyValue, if there is muliple columns query then you just need to append individual column filter by adding & between them.
For eg. if you need to filter records by considering 2 column values then your query be like PropertyOne=PropertyOneValue&PropertyTwo=PropertyTwoValue (Appending them by & symbol)
Please try below modified query we hope its works for you.
{% for row in hubdb_table_rows(676060,"windows=3&webcategory=CASHBOARD&limit=12") %}