Table Name Mapping not working in EF 6 when using POCO classes

I am using System.ComponentModel.DataAnnotations.Schema.TableAttribute in class below, so class 'Order_Details' is mapped to table 'Order Details' in Northwind database.

There is an attribute [Table("Order Details"] just above class definition to map it to a database table.

The problem is when a LINQ query executes against the database, it tries to query 'Order_Details' table in the database, when it should be querying 'Order Details' table.

Question: Do I have to use some other attribute for mapping this class to 'Order Details' table in the database? This POCO class ( without the table attribute) was generated by a third-party code generator using Entity Framework.

[Table("Order Details")]
public class Order_Details
{
    [Key]
    [Column(Order = 0)]
    [Required]
    [Display(Name = "Order I D")]
    public Int32 OrderID { get; set; }

    [Key]
    [Column(Order = 1)]
    [Required]
    [Display(Name = "Product I D")]
    public Int32 ProductID { get; set; }

    [Required]
    [Display(Name = "Unit Price")]
    public Decimal UnitPrice { get; set; }

    [Required]
    [Display(Name = "Quantity")]
    public Int16 Quantity { get; set; }

    [Required]
    [Display(Name = "Discount")]
    public Decimal Discount { get; set; }

    // ComboBox
    public virtual Orders Orders { get; set; }
    public virtual Products Products { get; set; }

}

UPDATE 1:

Since there was no edmx file and it was using 'Code first fluent API' as suggested by Jeow Li Huan in his answer, I add a table mapping for 'Order Details' in modelcreating event and it worked then.

protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);

            //added this in place of Table attribute and it works
            modelBuilder.Entity<Order_Details>().ToTable("Order Details");

            modelBuilder.Entity<Orders>().ToTable("Orders");
            modelBuilder.Entity<Products>().ToTable("Products");
            modelBuilder.Entity<Customers>().ToTable("Customers");
            modelBuilder.Entity<Employees>().ToTable("Employees");
            modelBuilder.Entity<Shippers>().ToTable("Shippers");
            modelBuilder.Entity<Suppliers>().ToTable("Suppliers");
            modelBuilder.Entity<Categories>().ToTable("Categories");

        }

UPDATE 2:

Also, another solution as suggested by Jeow, was to remove the model creating event and just use the original table attribute. This also worked.