name the common home port of the uscgc thetis and uscgc thetis ?
SELECT DISTINCT var_uri where brack_open dbr_USCGC_Thetis_ attr_open WMEC-910 attr_close dbo_homeport var_uri sep_dot dbr_USCGC_Thetis_ attr_open WMEC-910 attr_close dbo_homeport var_uri brack_close