When we try to query the ls_dr10.tractor, all columns in the resulting table have format str1. The pattern we are using follows below. It appears to work correctly for ls_dr9.tractor, but not ls_dr10.tractor.
The same query works with, e.g., the noirlab online query tool; it seems specific to the combination of pyvo and ls_dr10.tractor.
import pyvo
ra, dec, search_radius_deg, i_limit = 180., -1., 0.2, 18
tap_service = pyvo.dal.TAPService("https://datalab.noirlab.edu/tap")
ex_query = f"""SELECT ls_id, ra, dec, mag_g, mag_r FROM ls_dr10.tractor
WHERE 't' = Q3C_RADIAL_QUERY(ra,dec,{ra:.6f},{dec:+.6f},{search_radius_deg:.6f}) AND mag_r< {i_limit}
"""
result = tap_service.search(ex_query)
print(result)