When I read a '.mdb' file using pyodbc+pandas(pd.read_sql), There are difference(Time data) between source data and memory data

Question

I want to read mdb file to memory. but there are some difference between source data and memory data

Here are code

import pyodbc
import pandas as pd
import datetime
DB_Connection = pyodbc.connect('DRIVER={Microsoft Access Driver (*.mdb)};DBQ=./test_Time.mdb' )
DF_SaveData = pd.read_sql( 'SELECT * From SaveData',DB_Connection,parse_dates=True).sort_values(by='Date_Time',ascending=True)
print(DF_SaveData)

mdb data time : 2021-03-22 AM 8:45:46 result time : 2021-03-22 AM 8:45:45

1 second error...