如果数据库中没有列，如何应用条件？C＃

我正在用 C# 学习 SQLite 数据库。我需要帮助。如何进行检查 - 当没有列时（例如， with login，然后 output label1.text = "Такого пользователь нету!"）

        public Form1()
        {
            InitializeComponent();
            if (!File.Exists(@"F:\c#Learn\DataBaseAndUILearn\logining\login\login\logins.db"))
            {
                SQLiteConnection.CreateFile(@"F:\c#Learn\DataBaseAndUILearn\logining\login\login\logins.db");
            }
            using (SQLiteConnection Connect = new SQLiteConnection(@"Data Source = F:\c#Learn\DataBaseAndUILearn\logining\login\login\logins.db"))
            {
                string commandDb = "CREATE TABLE IF NOT EXISTS [user](" +
                    "[login] TEXT," +
                    "[password] TEXT)";
                SQLiteCommand command = new SQLiteCommand(commandDb, Connect);
                command.Connection.Open();
                command.ExecuteNonQuery();
            }
        }
        private void button1_Click(object sender, EventArgs e)
        {
            string logins = $"SELECT [login] FROM [user] WHERE [login] = '{loginInput.Text}'";
            using (SQLiteConnection Connect = new SQLiteConnection(@"Data Source = F:\c#Learn\DataBaseAndUILearn\logining\login\login\logins.db"))
            {
                SQLiteCommand command = new SQLiteCommand(logins, Connect);
                command.Connection.Open();
                SQLiteDataReader reader = command.ExecuteReader();
                while (reader.Read())
                {
                    label1.Text = "Добро пожаловать," + reader.GetString(0);
                }
            }
        }

UPD

        private void button1_Click(object sender, EventArgs e)
        {
            string logins = $"SELECT [login] FROM [user] WHERE [login] = '{loginInput.Text}'";
            using (SQLiteConnection Connect = new SQLiteConnection(@"Data Source = F:\c#Learn\DataBaseAndUILearn\logining\login\login\logins.db"))
            {
                SQLiteCommand command = new SQLiteCommand(logins, Connect);
                command.Connection.Open();
                SQLiteDataReader reader = command.ExecuteReader();
                while (reader.Read())
                {
                    string userName = reader.GetString(0);
                    label1.Text = userName;
                    if (userName == null)
                    {
                        label1.Text = "test";
                    }
                    else
                    {
                        label1.Text = "Добро пожаловать," + reader.GetString(0);
                    }
                }
            }
        }