I want to make sure I understand your question.  I translate your original text to:
“An Phu Town, An Minute District, An Giang Province”
(btw- why are there underscores in those places?  If you are manually tying the words together, is that a common practice?)
So I guess you are expecting something like

*     thị_trấn an_phú huyện an phútỉnh an_giang
*     Thi_trấn,  ‘an_@@’,   ‘phú’,    huyện,    an,         ‘phú@@’,   ‘tỉnh’,     ‘an_@@’,    ‘giang’’
*     "O",       "B-LOC",   "I-LOC",  "I-LOC"   "B-LOC",    "I-LOC"    "I-LOC",    "B-LOC",    "I-LOC"
*     “An Phu Town, An Minute District, An Giang Province”


Is that what you are expecting?