SQLITE delete and update in loop not working as expected.

The code below will not completely delete all rows from the SQLite database and update it as expected.

Input is a two dimensional array with all indexes assigned a value. During the first loop all rows of tbl_one are deleted, proceeded by the insertion of a new row, and then insertion of more rows as the loop progresses.

a = ['1;Value', '2;Value', '3;Value']

for i, value in enumerate(a):

   if i == 0:

      internaldatabase(self).execute('''Delete from tbl_one''')

   a[i] = list(value.split(";"))

   internaldatabase(self).execute('''INSERT INTO tbl_one(collum1, collum2) VALUES (?,?)''', (a[i][0], a[i][1]))

If all rows are selected then output would be:

1 Value 2 Value 3 Value 1 Value 2 Value 1 Value

Where as I would expect it to be:

1 Value 2 Value 3 Value

In the function internaldatabase the isolation_level is set to None, indicating implicit commits.

def internaldatabase(self):

    p = sys.path[0]+'''resource path'''

    p = sqlite3.connect(p, isolation_level=None)

    p = p.cursor()

    return(p)

I have already tried commit() and deleting/recreating the database, both with the same results.