import os
import csv
import xlrd

with xlrd.open_workbook('Pilvetyybid_1968_Jõgeva.xls') as wb:
    sh = wb.sheet_by_index(0)  # or wb.sheet_by_name('name_of_the_sheet_here')
    with open('a_file.csv', 'w', newline='') as f:
        spamwriter = csv.writer(f, delimiter=';', quotechar='|')
        c = csv.writer(f)
        for col in range(1,(sh.ncols),10):
            for row in range(sh.nrows):
                if sh.row!=None:
                    c.writerow(sh.row_values(sh.nrows-1))
                else:
                    pass