Log Analytics supports the creation of linked BigQuery datasets which let BigQuery have read access to the underlying data.

The correct and supported method to programmatically query the data within the my_project.global._Default._Default dataset is through the BigQuery API.

There are duplicate log entries in your Log Analytics results. Log Analytics doesn't perform the same type of deduplication that is performed by the Logs Explorer. To resolve duplicate log entries, you may try the list of items provided in the document.