I have faced following error while running data migration for 2nd time from 1.9.2.4 to 2.3.1
SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '1-Migration_Default' for key 'EA V_ATTRIBUTE_SET_ENTITY_TYPE_ID_ATTRIBUTE_SET_NAME'
I have faced following error while running data migration for 2nd time from 1.9.2.4 to 2.3.1
SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '1-Migration_Default' for key 'EA V_ATTRIBUTE_SET_ENTITY_TYPE_ID_ATTRIBUTE_SET_NAME'
This error generate because, that attribute set id already exist in database.
To solve this error, install blank Magento database in your Magento. Then, start again migration process.
Hope, it will helpful for you.