[datafusion] datafusion cannot recognize chinese charactors?

[Shao Grant]

I'm testing the datafusion and like it very much.
but I found it cannot recognize the chinese charactors, how to solve it?
my simple code as below: (using the python for example)
```
# encoding=utf8
use datafusion::prelude::*;

#[tokio::main]
async fn main() -> datafusion::error::Result<()> {
  // register the table
  let ctx = SessionContext::new();
  ctx.register_csv("example", "lite.csv", CsvReadOptions::new()).await?;

  // create a plan to run a SQL query
  let df = ctx.sql("SELECT distinct 扫描人 FROM example").await?;

  // execute and print results
  df.show().await?;
  Ok(())
}

Error: SQL(ParserError("Expected an expression:, found: 扫"))
```