import pandas as pd

url = "http://www.sejm.gov.pl/Sejm9.nsf/agent.xsp?symbol=glosowania&NrKadencji=9&NrPosiedzenia=18&NrGlosowania=1"

df = pd.read_html(url, encoding='utf-8')[0]

columns = [c for c in df.columns.to_list() if c!="Klub/Koło"]
objects = [x for x in columns if df[x].dtype==object and x!="Klub/Koło"]

def obj_to_int(df,columns):
    for c in columns:
        df[c] = df[c].map(lambda x: 0 if x=="-" else int(x))
    return df

df2 = obj_to_int(df, columns)
print(df2)

df2.to_csv("sejm.csv")